Electrodyne 511b – Two-Band Inductor EQ

OVERVIEW

The Electrodyne 511b is a feature-updated and greatly expanded version of the legendary 511 two-band discrete-transistor active inductor EQ. The 511b uses the same vintage design inductors, opamps and transformers as the 511 and original Electrodyne 711L EQ from 1970. Custom inductors and transformers are still made by the original manufacturer to strict factory tolerances as precise as 2% and high quality film capacitors are used throughout all EQ circuits. This allows consistent EQ repeatability from channel to channel that was not possible in the ’60s & ’70s, as well as smooth performance and response from minimum to maximum gain at all frequencies that provides unusually musical sonic and tonal options, not experienced since the 1970s.

KEY HIGHLIGHTS

Expanded EQ Selections:

Offers 23 more EQ selections than the original 511 for a total of 36, enhancing tonal precision.

Vintage-Inspired Design:

Uses original inductors, opamps, and transformers from the 1970s for authentic sound.

Precision Recall & Mastering:

Stepped-gain pots with 1 dB increments ensure precise recall and mastering capabilities.

Smooth, Musical Performance:

Consistent EQ response across all frequencies for exceptional clarity and character.

Compatible with Original 511:

Matches perfectly with the 511 for stereo pair use with identical settings.

FEATURES

• 36 EQ selections in total – 23 more than the 511:
  • 25 Peak selections in total – 6 Peaking positions per band with standard and narrow bandwidth on each, plus one bonus frequency.
  • 12 Shelf selections in total – 6 Shelving positions per band.
• Stepped-gain pots with 1db steps from +/-1db to +/-6db, and unity-gain calibration trimmer for precision recall and mastering use.
• Special note: The 511b includes all EQ selections, curves and performance found on the 511, so 511 and 511b EQs can be used together as stereo matched pairs when set to the same Peak / Shelf, bandwidth and gain settings.

TECHNICAL SPECS

Input: Active balanced discrete transistor impedance converter.

Output Impedance: 150 ohms, Transformer balanced.

+/-12 db Gain Range, Boost or Cut.

Peaking Frequencies Available per Band:

• LF: 150hz, 250hz, 350hz, 500hz., 750hz, 1khz, 1.5khz Standard and Narrow bandwidth available up to 1khz, 1.5khz fixed at narrow bandwidth.
• HF: 1.5khz, 2khz, 3khz, 5khz, 7khz, 10khz. Standard and Narrow bandwidth available on all frequencies.

Shelving Frequencies Available per Band:

• LF: 40hz, 100hz, 250hz, 500hz., 700hz
• HF: 1.5khz, 3khz, 5khz, 7khz, 10khz, 12khz

Distortion: 0.03%typical.

Maximum Output: +30db at less than 0.8%thd. (+29.5db at 0.06%thd)

Frequency Response: +/- 0.25db, 10hz to 70khz typical.

Signal to Noise: -85db typ.